So do we have a source on this outside of someone claiming to have a source on twitter... Pretty damning if it's true, but I'd like to see this from a more credible source.

There's three journalists confirming it on Twitter, one from Sportsnet, one from NY Post, and one from the New York Daily News. In addition to that you have Russo more or less confirming it as well. That's a lot of media support for something claimed as fact for it to be made up.

Could they all have the same one or two sources who are making something up? Possible, but unlikely.